Carbon is the fourth most abundant element in the universe, and it is the basis of all organic matter. Plants, such as trees, are made from air and water - they use the sun's energy to take in carbon from the air and create growth. When the plant dies and rots, or we burn it, the carbon in it combines with oxygen in the air to make the invisible gas Carbon Dioxide (CO2), which goes back into the air to be taken back up by new plant growth. As long as the fuel is renewed this simple cycle is in balance, all is well. But we humans have been burning huge amounts of the coal, oil and gas which are the fossil of organic material which died millions of years ago and so are releasing vast quantities of stored-up carbon into the atmosphere very quickly. It appears to be the case that this carbon build-up is increasing the 'greenhouse effect' and making the earth get warmer. The temperature rise has only been a degree or so over the last 100 years, but, unless something is done to reduce carbon emissions there is a fear that this warming may become very dangerous.

Heating accounts for nearly half of the UK’s carbon emissions, and the UK Climate Change Act has promised to reduce carbon emissions from the 1990 level by at least 80% by 2050.

Coal, oil and gas are all major emitters of carbon, and therefore need to be used with great care. But burning Wood Fuel, and other recently-harvested biofuels, can never emit more carbon than the plant took in when it was alive. As long as new growth is planted as the old growth is burned - and that is what happens throughout Europe - then biofuels are considered to be "carbon neutral", apart from a small carbon 'overhead' from the fossil fuels like oil used to process and transport them. (Electricity is the highest carbon emitter because, even though it produces no emissions at the point of use, it is largely made using coal and at relatively poor efficiency.)